Sight for Sore Eyes: Augmented Reality without the Discomfort

New goggle-like device may lead to 3-D augmented reality technology
that minimizes visual fatigue

(a) Set-up of the experiment. (b) To create a 3-D scene, the micro integral imaging display combines many views of the scene from different perspectives. Here, a 3-D depiction of the characters "3D" is decomposed into its various perspective views. (c) – (f) These pictures show that the artificial 3-D image behaves as if it were a real object in front of you. In (c) and (d), the Snelling chart on the left is placed about 4 m away while the grating on the right is 30 cm away. The number "3" was created to appear farther away while the letter "D" appears closer. As a result, when the focus of the camera shifts from far (c) to near (d), so does the focus of the "3" and "D." When the position of the camera moves a little to the right from (e) to (f), the perspective of “3D" also slightly shifts. Credit: Optics Express.

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(a) Set-up of the experiment. (b) To create a 3-D scene, the micro integral imaging display combines many views of the scene from different perspectives. Here, a 3-D depiction of the characters "3D" is decomposed into its various perspective views. (c) – (f) These pictures show that the artificial 3-D image behaves as if it were a real object in front of you. In (c) and (d), the Snelling chart on the left is placed about 4 m away while the grating on the right is 30 cm away. The number "3" was created to appear farther away while the letter "D" appears closer. As a result, when the focus of the camera shifts from far (c) to near (d), so does the focus of the "3" and "D." When the position of the camera moves a little to the right from (e) to (f), the perspective of “3D" also slightly shifts. Credit: Optics Express.

WASHINGTON--(BUSINESS WIRE)--Augmented reality is increasingly becoming… well … a reality. Smartphone
apps can point out restaurants as you scan the street with your phone
camera or even identify constellations when you point your phone at the
night sky. And goggle-like devices—akin to Google Glass—that you wear on
your head can superimpose computer-generated images onto your direct
view of the physical world.

But one major limitation of this kind of augmented reality (AR)
technology is that moving back and forth between a 2-D image on the
screen and a 3-D world in front of you causes eye strain, unless you’re
looking at something far away. Now a new device developed by researchers
at the University of Arizona in Tucson and the University of Connecticut
in Storrs is making AR technology easier on the eyes for short-distance
applications, too, by superimposing 3-D images instead of 2-D. The
authors describe their new approach in a paper published today in The
Optical Society’s (OSA)
open-access journal Optics
Express.

"Minimizing visual discomfort involved in wearing AR displays remains an
unresolved challenge," says first author Hong Hua of the University of
Arizona. "This work is making a significant step forward in addressing
this important issue."

A lightweight, compact and high-performance Google Glass-like
device—called an optical see-through head-mounted display
(OST-HMD)—could potentially be “a transformative technology to redefine
the way we perceive and interact with digital information,” Hua says.
For example, it could one day allow a doctor to see computed tomography
(CT) images overlaid on a patient's abdomen during surgery or provide a
new way to train soldiers by incorporating 3-D virtual objects into
real-life environments.

AR goggles for long-distance viewing don’t always cause eye strain; some
of these eye-friendly designs are actively used for military
applications. But short-distance designs—in which you would focus
simultaneously on a 2-D screen and a 3-D world immediately around you—do
cause visual discomfort, due to the so-called accommodation-convergence
mismatch problem.

"The eyes are going back and forth between the screen and the
three-dimensional scene away from the screen, causing conflicting depth
perception cues and visual fatigue," Hua explains.

The device developed by Hua and her colleague Bahram Javidi of the
University of Connecticut solves this problem for OST-HMDs by
superimposing a 3-D image, rather than the standard 2-D image, onto the
3-D view of the real world.

To create the 3-D image, the researchers developed a technology called
microscopic integral imaging display. In this technique, a tiny,
high-resolution screen produces views from different perspectives of the
3-D image you want to superimpose. The views then combine to reconstruct
a 3-D scene that's sent through a specially shaped optical lens—called a
freeform eyepiece—and into the eye. The lens, based on an emerging
technology known as freeform optics, also allows you to directly see the
real-life scene before you.

The result is a superimposition of a 3-D image onto a direct view of
reality, allowing you to see the virtual image as if it were a real, 3-D
object in the physical space in front of you. There's no conflict in how
your eyes focus, giving you a much more comfortable version of augmented
reality, Hua says.

Still, much work remains before the device is ready for
commercialization, she says. In particular, the researchers hope to
improve the depth and spatial resolution, as well as the viewing angle
of the microscopic integral imaging technology and the freeform
eyepiece. But due to rapid improvements in commercially available
optical and optoelectronic devices, the prospects for commercialization
are promising, Javidi adds.

Images are available to members of the media upon request. Contact
Angela Stark, astark@osa.org.

Augmented reality and wearable displays is a featured topic at the
upcoming OSA
Imaging and Applied Optics: Optics and Photonics Congress, July
13- 17 in Seattle, Washington, USA. Bernard Kress, optics lead of the
Google Glass Project, will be a plenary
speaker, in addition to other invited and contributed talks on the
topic. Reporters interested in obtaining a press badge to cover the
OSA Imaging Congress should contact Angela Stark, astark@osa.org.

About Optics Express

Optics Express reports on new developments in all fields of
optical science and technology every two weeks. The journal provides
rapid publication of original, peer-reviewed papers. It is published by
The Optical Society and edited by Andrew M. Weiner of Purdue University. Optics
Express is an open-access journal and is available at no cost to
readers online at www.OpticsInfoBase.org/OE.

About OSA

Founded in 1916, The Optical Society (OSA) is the leading professional
society for scientists, engineers, students and business leaders who
fuel discoveries, shape real-world applications and accelerate
achievements in the science of light. Through world-renowned
publications, meetings and membership programs, OSA provides quality
research, inspired interactions and dedicated resources for its
extensive global network of professionals in optics and photonics. For
more information, visit www.osa.org.